Experiment 11

AE 315 (06) Experiment 11: Propeller Performance November 19th, 2009 Ajay Abraham

1.

Introduction The basic theory in this experiment is that the angle of attack, α of the propeller blade is dependent on the geometric pitch of the blade, β and the advance angle, φ which is dependent upon the resultant velocity that the propeller sees. When α decreases, the lift of the blade decreases while the drag increases. Hence, the thrust of the propeller decreases. The objective of this experiment is to determine the relationship between β, power, RPM of the blade and the thrust of the propeller at static condition (no wind, =0) and the relationship between RPM of the blade, and the thrust of the propeller at non static conditions for constant power and power off. In this experiment, different propeller blades with different β angles are placed in the test section and tested at varying power with the wind tunnel idle. Then, the propeller blade with the higher β angle is tested at a constant power and no power condition with the tunnel running at varying RPM.

2.

Experimental Setup 2.1 Equipment In accordance with the lab manual. 2.2 Sequence of Operations In accordance with the lab manual. 2.3 Sketch of Equipment Setup

Figure 1, Studying characteristics of a propeller

3.

Results 3.1 Measured Data

Table 1, Measured Data

β

LOW

HIGH

POWER (watts)

RPM

50 100 150 200 250 300 50 100 150 200 250 300 300 300 300 300 300 0 0 0 0 0

2800 3620 4240 4745 5160 5530 2000 2640 3170 3545 3870 4145 4362 5630 6900 7800 8520 2400 4590 6170 7180 7960

(ft s-1)

(lbf)

0 0 0 0 0 0 0 0 0 0 0 0 50.95 94.18 127.02 147.78 164.14 48.58 93.03 126.52 148.01 163.59

0.37 0.70 1.22 1.65 1.99 2.40 0.51 0.97 1.41 1.80 2.17 2.51 1.61 0.77 0.05 -0.49 -1.00 -0.29 -0.77 -1.21 -1.66 -2.06

3.2

List of Equations In accordance with the lab manual. 3.2.1

Sample Calculations

Does not apply. 3.3 Final Results 3.3.1

Tables Does not apply.

3.3.2 Plots

Figure 2, Graph of Static Thrust, F (lbf) versus RPM

StaticThrust, F(lbf) 3 2.5 2 1.5

LOW β

1

HIGH β

0.5

RPM

0 0

1000

2000

3000

4000

5000

6000

Figure 3, Graph of Static Power versus RPM

StaticPower 6000 5000 4000 3000

LOW β

2000

HIGH β

1000

RPM

0 0

100

200

300

400

Figure 4, Graph of Force, F (lbf) versus Vo (ft s-1)

Force, F(lbf) 3 2.5 2 1.5 1 0.5 0 -0.5 0 -1 -1.5

50

100

150

200 -1 Vo (ft s )

Figure 5, Graph of RPM versus Vo (ft s-1)

RPM 9000 8000 7000 6000 5000 4000

POWER ON

3000

POWER OFF

2000 1000 -1

Vo (ft s )

0 0

50

100

150

200

Figure 6, Graph of Force, F (lbf) versus Vo (ft s-1)

0

-1

0 -0.5 -1 -1.5 -2 -2.5

Force, F(lbf)

50

100

150

Vo (ft s ) 200

4.

Conclusion 4.1 Theory In accordance with the lab manual. 4.2 Verification of Theory 4.2.1 Referring to Figure 2, when β angle is increased at constant RPM and VO = 0, the thrust increases and the power required also increases. 4.2.2 Referring to Figure 5, the thrust drops as VO increases at constant power. 4.2.3 Referring to Figure 3, the RPM increases as VO increases at constant power. 4.2.4 Referring to Figure 6, the windmilling propeller produces drag. Referring to Figure 2, the windmilling propeller turns almost as fast as during full power for high VO values.